Effect of D‐mannitol on nitrogen retention,fiber digestibility and digesta transit time in adult rabbits

The aim of the current study was to elucidate the effect of gastrointestinal retention time of digesta on fiber digestibility in adult rabbits fed indigestible, but fermentable, sugar D‐mannitol. Six adult rabbits were fed alternately a commercial diet containing 5% glucose and a diet containing D‐mannitol. Total feces and urine were collected during the experimental period. Nitrogen (N) balance, digestibility of nutrients, and gastrointestinal mean retention time (MRT) were measured. The results indicated that urinary excretion was significantly lowered, whereas N retention and N accumulation rates were significantly increased in the D‐mannitol group compared with the glucose group (P < 0.05). However, fecal N excretion was unaffected. Absorption of crude ash (CA) and acid detergent fiber (ADF) digestibility were significantly higher in the D‐mannitol group compared with the glucose group (P < 0.05). The addition of D‐mannitol to the diet did not affect the MRT of liquid digesta, but increased the MRT of solid digesta compared with the glucose group (P < 0.05). These results suggest that the addition of D‐mannitol to the diet stimulates cecal bacterial growth, thereby increasing N utilization and digesta retention time.     

Effects of the sodium‐glucose cotransporter 2 (SGLT2) inhibitor velagliflozin,a new drug with therapeutic potential to treat diabetes in cats

Sodium‐glucose cotransporter 2 (SGLT2) inhibitors are used in the treatment of human diabetics. They increase glucose excretion and correct hyperglycemia. We examined the investigational SGLT2 inhibitor velagliflozin in two groups of six neutered adult obese cats (equal gender distribution). Placebo (Pl) or drug (D; 1 mg/kg) was administered for 35 days. Routine blood examinations, fructosamine, beta‐hydroxybutyrate (BHB), nonesterified fatty acids (NEFA), glucagon, adiponectin, and leptin were measured before and after treatment, also water intake, and urinary electrolytes, glucose, and volume. Indirect calorimetry, an intravenous glucose tolerance test (IVGTT; 0.8 g/kg) and insulin tolerance test (IVITT) were conducted. All cats tolerated treatment well. Significant changes with D included a decrease in the respiratory exchange ratio, an increase in cholesterol, a small increase in albumin, and a rise in BHB and NEFA. Glucose clearance was unaltered, although less insulin was secreted during the IVGTT (p = .056) suggesting improved insulin sensitivity. IVITT was unchanged. Treatment did not affect glucagon, leptin, or adiponectin. Water intake, urine output, urinary glucose excretion, and the glucose/creatinine ratio but not urinary electrolytes were significantly higher post‐D. We conclude that velagliflozin is a promising drug, which increases urinary glucose excretion in cats and could thereby be beneficial for the treatment of hyperglycemia.     

Effects of concentrate‐to‐forage ratios and 2‐methylbutyrate supplementation on ruminal fermentation,bacteria abundance and urinary excretion of purine derivatives in Chinese Simmental steers

This study evaluated the effects of dietary concentrate levels and 2‐methylbutyrate (2MB ) supplementation on performance, ruminal fermentation, bacteria abundance, microbial enzyme activity and urinary excretion of purine derivatives (PD ) in steers. Eight ruminally cannulated Simmental steers (12 months of age; 389 ± 3.7 kg of body weight) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement. Moderate‐concentrate (400 g/kg diet [MC ]) or high‐concentrate (600 g/kg diet [HC ]) diets were fed with or without 2MB (0 g/day [2MB ?] or 15.0 g/day [2MB +]). Dry matter intake and average daily gain increased, but feed conversion ratio decreased with the HC diet or 2MB supplementation. Ruminal pH decreased, but total volatile fatty acid increased with the HC diet or 2MB supplementation. Molar proportion of acetate and acetate‐to‐propionate ratio decreased with the HC diet, but increased with 2MB supplementation. Propionate molar proportion and ruminal NH ₃‐N content increased with the HC diet, but decreased with 2MB supplementation. Neutral detergent fibre degradability decreased with the HC diet, but increased with 2MB supplementation. Crude protein degradability increased with the HC diet or 2MB supplementation. Abundance of Ruminococcus albus , Ruminococcus flavefaciens , Fibrobacter succinogenes and Bufyrivibrio fibrisolvens as well as activities of carboxymethyl cellulase, cellobiase, xylanase and pectinase decreased with the HC diet, but increased with 2MB supplementation. However, abundance of Prevotella ruminicola and Ruminobacter amylophilus as well as activities of α‐amylase and protease increased with the HC diet or 2MB supplementation. Total PD excretion also increased with the HC diet or 2MB supplementation. The results suggested that growth performance, ruminal fermentation, CP degradability and total PD excretion increased with increasing dietary concentrate level from 40% to 60% or 2MB supplementation. The observed diet × 2MB interaction indicated that supplementation of 2MB was more efficacious for improving growth performance, ruminal fermentation and total PD excretion with promoted ruminal bacteria abundance and enzyme activity in the MC diet than in the HC diet.     

Effect of fructo‐oligosaccharide on nitrogen utilization in guinea pigs

The present study was conducted to determine the effects of fructo‐oligosaccharide (FOS) on the nitrogen (N) utilization and digestibilities of dietary nutrients through cecotrophy in guinea pigs. Adult male guinea pigs that were housed or not housed in wooden frames to prevent cecotrophy were fed a commercial pellet diet (50 g/day) with 3% and 5% glucose or FOS for 8 days in individual metabolism cages. In the guinea pigs allowed cecotrophy, addition of FOS to the diet had no significant effects on body weight gain or apparent digestibility of N, but showed significantly lower value for the urinary N excretion and acid‐detergent fiber digestibility (P < 0.05 and P < 0.01, respectively) and significantly higher value for N retention and the N retention rate (P < 0.05). In the guinea pigs prevented from cecotrophy, FOS had no effect on N retention, but showed tendencies toward a higher value for fecal N excretion and a lower value for urinary N excretion. These results suggest that FOS stimulates cecal microbial proliferation, thereby improving N utilization in guinea pigs.     

Effects of (−)‐hydroxycitric acid on lipid droplet accumulation in chicken embryos

This study was conducted to determine the impact of (?)‐hydroxycitric acid ((?)‐HCA) on biochemical indices and lipid metabolism parameters in chicken embryos. Two hundred and forty fertilized eggs were divided into six groups and injected with (?)‐HCA at concentrations of 0, 0.1, 0.5, 1.0, 10.0 and 50 mg/kg (n = 40). After 19 days of incubation, serum and liver were collected for analysis of biochemical indices and lipid metabolism parameters. Results showed no significant differences on serum biochemical indices: 1–50 mg/kg (?)‐HCA significantly increased serum glucose and hepatic glycogen contents (P < 0.05). Oil Red O staining analysis showed total area, counts of lipid droplets and hepatic triglyceride content were significantly decreased (P < 0.01), meanwhile hepatic lipase and lipoprotein lipase activity were significantly increased (P < 0.05). ACLY, ME1, SREBP‐1c messenger RNA (mRNA) levels in 0.5–10 mg/kg groups and FAS mRNA level in 1–10 mg/kg groups were significantly decreased (P < 0.05), while PPARα mRNA level, serum adiponectin content and AdipoR1 mRNA level were significantly increased in 0.5–50 mg/kg groups (P < 0.05). These results indicated (?)‐HCA treatment inhibited triglyceride synthesis via decreasing lipogenesis‐related factors, mRNA expression level and accelerated lipolysis by enhancing lipoprotein lipase and hepatic lipase activity, which finally reduced lipid droplet accumulation, and this action may be associated with activating the adiponectin signaling pathway.     

Tyrosine‐derived 4‐hydroxyphenylpyruvate reacts with ketone test fields of 3 commercially available urine dipsticks

Background: The enzyme 4‐hydroxyphenylpyruvate dioxygenase (HPPD) is key in tyrosine catabolism. Inhibition of HPPD results in tyrosinemia and increased urinary excretion of 3 phenylketones: 4‐hydroxyphenylpyruvate (HPPA), 4‐hydroxyphenyllactate (HPLA), and 4‐hydroxyphenylacetate (HPAA). A previous study involving administration of a novel HPPD inhibitor to dogs resulted in detection of ketonuria in treated animals using urine dipsticks read by reflectance photometry. Dipstick‐positive results were suspected to be false because high concentrations of urinary phenylketones have been reported to react with ketone test fields of urine dipsticks, but visual confirmation was not performed. Objective: The purpose of this study was to determine which of the 4‐hydroxyphenolic acids produced by HPPD inhibition react with ketone test fields of 3 commercially available urine dipsticks. Methods: Canine urine samples were prepared with HPPA, HPLA, HPAA, and lithium acetoacetate (positive control) at 6 concentrations. Unmodified urine samples were used as negative controls. All samples were tested for ketones using Combur 10 Test M dipsticks read by a Miditron dipstick analyzer. Urinalysis was also performed by visually inspecting ketone test fields on the Combur 10 Test M, Multistix 10 SG, and Aution 10 EA dipsticks. Results: Urine samples containing HPPA were positive for ketones with Combur 10 Test M dipsticks read by the Miditron analyzer and produced a red–brown color change in ketone test fields of all 3 dipsticks. Urine samples containing HPLA and HPAA were negative by all methods. Conclusion: The phenylketone HPPA reacts with ketone test fields of 3 commercially available urine dipsticks, producing a red–brown color change that may be misinterpreted as positive for ketones by reflectance photometry.     

Utilization of dietary urea nitrogen is stimulated by D‐mannitol feeding in rabbits

The effect of D‐mannitol as an indigestible sugar on apparent digestibility of nutrients, nitrogen (N) utilization and growth performance, have been investigated in growing rabbits fed a urea‐containing diet. In experiment 1, 40‐day‐old male rabbits were fed a commercial diet with urea 10 g/kg with added glucose or D‐mannitol 60 g/kg each. Thereafter, in experiment 2 the rabbits aged 55 days were fed a commercial diet with or without urea 10 g/kg. Feed restriction at 55 g/kg^0.75/day was carried out in both experiments. Addition of D‐mannitol to the urea‐containing diet decreased urinary N excretion, which consequently increased N retention and ratios of retained N to consumed N or apparently absorbed N. Addition of urea alone to the diet increased daily N intake and urinary N excretion but did not affect N retention. Weight gain and feed efficiency were improved by D‐mannitol feeding, whereas feeding with urea alone did not affect these parameters. Utilization of dietary urea was enhanced in growing rabbits fed the urea‐containing diet with D‐mannitol, resulting in improvement of N retention and growth performance.     

Calming effect of orally administered γ‐aminobutyric acid in Shih Tzu dogs

The calming effects of γ‐aminobutyric acid (GABA) by oral administration were investigated in four adult Shih Tzu dogs. Three dosage levels (1, 2 and 4 mg/kg body weight) and non‐administration were tested by an increase and decrease method. Changes in activity (for 1.5 h) and urinary cortisol levels (pre‐administration, 3 and 7 h later) of dogs were monitored after administration. Without reference to dosage level, the mean times spent standing (P = 0.06), sitting (P < 0.05) and walking (P < 0.05) tended to decrease compared to non‐administration. A significant depression in the urinary cortisol level was observed at 7 h after administration (P < 0.05). These results indicate that orally administrated GABA exerts calming effects on dogs as well as humans.     

Estimation of Quantitative Enzymuria in Dogs With Gentamicin-Induced Nephrotoxicosis Using Urine Enzyme/Creatinine Ratios From Spot Urine Samples

The correlation between 24-hour urinary excretion of N -acetyl-β- d -glucosaminidase (NAG) and γ-glutamyl transferase (GGT) with urine NAG and GGT/creatinine ratios was assessed in dogs with gentamicin-induced nephrotoxicosis. Eighteen 6-month-oid male Beagles with normal renal function were randomly divided into 3 groups of 6. Each group was fed a different concentration of protein (high protein, 27.3%; medium protein, 13.7%; and low protein, 9.4%) for 21 days. After dietary conditioning, gentamicin was administered at a dose of 10 mg/kg IM tid for 8 days and each group was continued on its respective diet. Endogenous creatinine clearance and 24-hour urinary excretion of NAG and GGT were determined after dietary conditioning (day 0) and on days 2, 4, 6, and 8 of gentamicin administration. In addition, urine NAG and GGT/creatinine ratios (IU/L ± mg/dL) were determined from catheterized spot urine samples obtained between 7 and 10 am on the same days. The correlation between 24-hour urinary enzyme excretion and urine enzyme/creatinine ratio in the spot urine samples was evaluated by simple linear regression analysis. Spot sample urine enzyme/creatinine ratios were significantly correlated with 24-hour urinary enzyme excretion through day 4 for dogs on low dietary protein, through day 6 for those on medium protein, and through day 8 for those on high dietary protein. Mean ± SD baseline values for urine NAG/creatinine ratio and 24-hour urinary NAG excretion were 0.06 ± 0.04 and 0.19 ± 0.14 IU/kg/24 hr, respectively. Baseline values for urine GGT/creatinine ratio and 24-hour urinary GGT excretion were 0.39 ± 0.18 and 1.42 ± 0.82 IU/kg/24 hr, respectively.     

An appraisal of the in vivo role of phosphate as a modulator of urinary ammonium and titratable acid excretion in the acidotic rabbit

Previous studies have shown that the intravenous infusion of inorganic phosphate increased urinary ammonium excretion 8‐ to 10‐fold in the acidotic rabbit. This was considered to be a very important observation at the time and to be unique to the rabbit. While investigating this finding, we discovered that the formol titration procedure, used to measure urinary ammonium by this research group, is subject to interference by phosphate, casting doubt on the validity of the urinary ammonium excretion data reported by them in the literature. In order to re‐assess the importance of phosphate as a potential modulator of urinary ammonium excretion in the acidotic rabbit, renal net acid excretion studies were carried out in phosphate‐loaded acidotic animals. We observed that while urinary ammonium excretion increased significantly (p < 0.05) after 50 min of phosphate infusion, the maximum concentrations excreted were substantially less than previously reported in the literature. However, through its urinary buffering capacity, we observed that inorganic phosphate, via an experimentally induced phosphaturia, could substantially enhance titratable acid excretion. Contrary to earlier reports, we demonstrated that phosphate plays a relatively minor in vivo modulator role in enhancing renal net acid excretion through the vehicle of ammonium during acute metabolic acidosis in the hyperphosphataemic rabbit. The findings reported in this study constitute an important update on ammonia metabolism in the acidotic rabbit.     

Potential role of ALDH3A2 on the lipid and glucose metabolism regulated by (‐)‐hydroxycitric acid in chicken embryos

This study aimed to investigate the effect of (‐)‐hydroxycitric acid ((‐)‐HCA) on lipid and glucose metabolism, and further analyzed these actions whether associated with modulation of aldehyde dehydrogenase 3 family member A2 (ALDH3A2) expression in chicken embryos. Results showed that (‐)‐HCA decreased triglyceride content and lipid droplet counts, while these effects induced by (‐)‐HCA were reversed in chicken embryos pre‐transfected with sh4‐ALDH3A2. (‐)‐HCA decreased malic enzyme, acetyl‐CoA carboxylase, fatty acid synthase, and sterol regulatory element binding protein‐1c mRNA level, while increased carnitine palmitoyl transferase 1A (CPT1A) and peroxisome proliferators‐activated receptor α (PPARα) mRNA level; and the action of (‐)‐HCA on lipid metabolism factors had completely eliminated in embryos pre‐transfected with sh4‐ALDH3A2. Chicken embryos pre‐transfected with sh4‐ALDH3A2 had eliminated the increasing of serum glucose and hepatic glycogen content induced by (‐)‐HCA. (‐)‐HCA decreased phosphofructokinase‐1 and increased G6P, fructose‐1,6‐bisphosphatase, phosphoenolpyruvate carboxykinase (PEPCK), and pyruvate carboxylase mRNA level in chicken embryos. Similarly, the effect of (‐)‐HCA on these key enzyme mRNA level was reversed in embryos pre‐transfected with sh4‐ALDH3A2. Furthermore, (‐)‐HCA increased PPAR‐γ‐coactivator‐1α (PGC‐1α), PPARα, hepatic nuclear factor‐4A, PEPCK, and CPT1A protein level, and these actions of (‐)‐HCA disappeared in embryos pre‐transfected with sh4‐ALDH3A2. These results indicated that (‐)‐HCA reduced fat accumulation and accelerated gluconeogenesis via activation of PGC‐1α signaling pathway, and these effects of (‐)‐HCA might associate with the increasing of ALDH3A2 expression level in chicken embryos.     

Supplemental lipoic acid relieves post‐weaning diarrhoea by decreasing intestinal permeability in rats

Lipoic acid (LA) is a naturally existing substance which widely distributed in the cellular membranes and cytosol of animal cells. Its intracellular functions include quenching of free radicals and repairing oxidized proteins. The purpose of this study was to evaluate the effects of LA on post‐weaning diarrhoea using a rat model. Sixty weaned rats were fed either a basal diet or a LA‐supplemented diet, or a zinc oxide (ZnO)‐supplemented diet as a positive control. Rats in the LA and ZnO groups had better performance and reduced incidence of diarrhoea (p < 0.05). Both LA and ZnO treatments enhanced intestinal homeostatic and architecture, significantly decreased urinary lactulose to mannitol ratios (p < 0.05) and increased the expression of the intestinal mucosal tight junction proteins occludin (OCLN) and zonula occludens protein‐1 (ZO‐1) (p < 0.05). LA significantly increased the activities of antioxidant enzymes, and reduced glutathione while decreasing the levels of oxidative glutathione and malondialdehyde in the intestinal mucosa (p < 0.05). Furthermore, an in vitro study indicated that supplementation with LA in IEC‐6 intestinal epithelial cells significantly enhanced the expression of OCLN and ZO‐1 under hydrogen peroxide‐induced oxidative stress. Collectively, these results suggest that LA relieves post‐weaning diarrhoea by reducing intestinal permeability and improving antioxidant indices.     

COMPARISON BETWEEN 2‐18F‐FLUORO‐2‐DEOXY‐D‐GLUCOSE POSITRON EMISSION TOMOGRAPHY AND CONTRAST‐ENHANCED COMPUTED TOMOGRAPHY FOR MEASURING GROSS TUMOR VOLUME IN CATS WITH ORAL SQUAMOUS CELL CARCINOMA

Feline oral squamous cell carcinoma is one of the most refractory feline malignancies. Most patients succumb due to failure in local tumor control. 2‐¹⁸F‐fluoro‐2‐deoxy‐D‐glucose positron emission tomography (¹⁸F‐FDG PET) is increasingly being used for veterinary oncology staging as it highlights areas with higher glucose metabolism. The goal of the current prospective study was to compare gross tumor volume measurements using ¹⁸F‐FDG PET vs. those using computed tomography (CT) for stereotactic radiation therapy planning in cats with oral squamous cell carcinoma. Twelve cats with confirmed oral squamous cell carcinoma underwent pretreatment ¹⁸F‐FDG PET/CT. Gross tumor volumes based on contrast‐enhanced CT and ¹⁸F‐FDG PET were measured and compared among cats. Mean PET gross tumor volume was significantly smaller than mean CT gross tumor volume in the mandibular/maxillary squamous cell carcinoma group (n = 8, P = 0.002) and for the total number of patients (n = 12, P = 0.006), but not in the lingual/laryngeal group (n = 4, P = 0.57). Mismatch fraction analysis revealed that most of the lingual/laryngeal patients had a large region of high‐¹⁸F‐FDG activity outside of the CT gross tumor volume. This mismatch fraction was significantly greater in the lingual/laryngeal group than the mandibular/maxillary group (P = 0.028). The effect of poor spatial resolution of PET imaging was greater when the absolute tumor volume was small. Findings from this study indicated that ¹⁸F‐FDG PET warrants further investigation as a supplemental imaging modality in cats with oral squamous cell carcinoma because it detected regions of possible primary tumor that were not detected on CT images.     

Immunohistochemical expression of p63, Ki67 and β‐catenin in canine transitional cell carcinoma and polypoid cystitis of the urinary bladder

Transitional cell carcinoma (TCC) is a urinary bladder tumour associated with high mortality in dogs. In this study, we investigated the feasibility of using p63, Ki67 or β‐catenin as a clinical marker for predicting biological behaviour and prognosis in canine TCC. Expression levels of these proteins in TCC (n = 25), polypoid cystitis (n = 5) and normal urinary bladder (n = 5) were scored after immunohistochemical staining. The staining scores for p63 (P < 0.01) and β‐catenin (P < 0.05) in TCC were significantly lower than those in normal urinary bladder and polypoid cystitis. In contrast, Ki67 (P < 0.01) staining scores in TCC were significantly higher than those in normal urinary bladder and polypoid cystitis. In TCC, low p63 expression was significantly related to the presence of vessel invasion (P < 0.05) and metastasis (P < 0.01) as well as short survival time (P < 0.05). These findings show that p63 could be a reliable marker for predicting prognosis in canine TCC.     

Multiple‐Aetiology Enteric Infections Involving Non‐O157 Shiga Toxin‐Producing Escherichia coli – FoodNet, 2001–2010

We describe multiple‐aetiology infections involving non‐O157 Shiga toxin‐producing Escherichia coli (STEC) identified through laboratory‐based surveillance in nine FoodNet sites from 2001 to 2010. A multiple‐aetiology infection (MEI) was defined as isolation of non‐O157 STEC and laboratory evidence of any of the other nine pathogens under surveillance or isolation of >1 non‐O157 STEC serogroup from the same person within a 7‐day period. We compared exposures of patients with MEI during 2001–2010 with those of patients with single‐aetiology non‐O157 STEC infections (SEI) during 2008–2009 and with those of the FoodNet population from a survey conducted during 2006–2007. In total, 1870 non‐O157 STEC infections were reported; 68 (3.6%) were MEI; 60 included pathogens other than non‐O157 STEC; and eight involved >1 serogroup of non‐O157 STEC. Of the 68 MEI, 21 (31%) were part of six outbreaks. STEC O111 was isolated in 44% of all MEI. Of patients with MEI, 50% had contact with farm animals compared with 29% (P < 0.01) of persons with SEI; this difference was driven by infections involving STEC O111. More patients with non‐outbreak‐associated MEI reported drinking well water (62%) than respondents in a population survey (19%) (P < 0.01). Drinking well water and having contact with animals may be important exposures for MEI, especially those involving STEC O111.     

Dietary supplementation with glutamine and γ‐aminobutyric acid improves growth performance and serum parameters in 22‐ to 35‐day‐old broilers exposed to hot environment

This study was designed using 360 21‐day‐old chicks to determine the influences of diet supplementation with glutamine (5 g/kg), γ‐aminobutyric acid (GABA, 100 mg/kg) or their combinations on performance and serum parameters exposed to cycling high temperatures. From 22 to 35 days, the experimental groups (2 × 2) were subjected to circular heat stress by exposing them to 30–34 °C cycling, while the positive control group was exposed to 23 °C constant. The blood of broilers was collected to detect serum parameters on days 28 and 35. Compared with the positive control group, the cycling high temperature decreased (p < 0.05) the feed consumption, weight gain and serum total protein (TP), glucose, thyroxine (T4), insulin, alkaline phosphatase (ALP), glutamine, GABA and glutamate levels, while increased (p < 0.05) the serum triglyceride (TG), corticosterone (CS), glucagon (GN), creatine kinase (CK), glutamic oxaloacetic transaminase (GOT), nitric oxide synthase (NOS), glutamate pyruvate transaminase (GPT) and lactate dehydrogenase (LDH) levels during 22–35 days. However, dietary glutamine (5 g/kg) increased (p < 0.05) the feed consumption, weight gain and serum levels of glutamine, TP, insulin and ALP, but decreased (p < 0.05) the serum TG, CK, GOT, NOS and GPT levels. Diet supplemented with GABA also increased (p < 0.05) weight gain and the serum levels of TP, T4, ALP, GABA and glutamine. In addition, the significant interactions (p < 0.05) between glutamine and GABA were found in the feed consumption, weight gain and the serum ALP, CK, LDH, GABA, T3 and T4 levels of heat‐stressed chickens. This research indicated that dietary glutamine and GABA improved the antistress ability in performance and serum parameters of broilers under hot environment.     

Dietary α‐ketoglutarate supplementation improves hepatic and intestinal energy status and anti‐oxidative capacity of Cherry Valley ducks

α‐Ketoglutarate (AKG) is an extensively used dietary supplement in human and animal nutrition. The aim of the present study was to investigate effects of dietary AKG supplementation on the energy status and anti‐oxidative capacity in liver and intestinal mucosa of Cherry Valley ducks. A total of 80 1‐day‐old ducks were randomly assigned into four groups, in which ducks were fed basal diets supplemented with 0% (control), 0.5%, 1.0% and 1.5% AKG, respectively. Graded doses of AKG supplementation linearly decreased the ratio of adenosine monophosphate (AMP) to adenosine triphosphate (ATP) in the liver, but increased ATP content and adenylate energy charge (AEC) in a quadratic and linear manner, respectively (P < 0.05). Increasing dietary AKG supplemental levels produced linear positive responses in ATP content and AEC, and negative responses in AMP concentration, the ratio of AMP to ATP and total adenine nucleotide in the ileal mucosa (P < 0.05). All levels of dietary AKG reduced the production of jejunal hydrogen peroxide and hepatic malondialdehyde (P < 0.05). Hepatic and ileal messenger RNA expression of AMP kinase α‐1 and hypoxia‐inducible factor‐1α were linearly up‐regulated as dietary AKG supplemental levels increased (P < 0.05). In conclusion, dietary AKG supplementation linearly or quadratically enhanced hepatic and intestinal energy storage and anti‐oxidative capacity of Cherry Valley ducks.     

Expression analysis of an α‐1, 3‐galactosyltransferase,an enzyme that creates xenotransplantation‐related α–Gal epitope,in pig preimplantation embryos

α‐1,3‐Galactosyltransferase (α‐GalT), an enzyme creating Galα1‐3Gal (α‐Gal) epitope on the cell surface in some mammalian species such as pigs, is known to be a key factor that causes hyperacute rejection upon transplantation from pigs to humans. To establish the RNA interference‐based suppression of endogenous α‐GalT messenger RNA (mRNA) synthesis in porcine preimplantation embryos, we determined the suitable embryonic stage at which stage such approach is possible by using the semi‐quantitative RT‐PCR (qRT‐PCR) and the cytochemical method using a fluorescence‐labeled Bandeiraea simplicifolia Isolectin B₄ (BS‐I‐B₄). Staining with BS‐I‐B₄ demonstrated that α‐Gal epitope expression was first recognized at the 8‐cell stage, and increased up to the hatched blastocyst stage. Single embryo‐based qRT‐PCR also confirmed this pattern. These results indicate that creation of α‐Gal epitope is proceeded by de novo synthesis of α‐GalT mRNA in porcine preimplantation embryos with peaking at the blastocyst stage.     

Effects of high ambient temperature on urea‐nitrogen recycling in lactating dairy cows

Effects of exposure to hot environment on urea metabolism were studied in lactating Holstein cows. Four cows were fed ad libitum a total mixed ration and housed in a temperature‐controlled chamber at constant moderate (18°C) or high (28°C) ambient temperatures in a cross‐over design. Urea nitrogen (N) kinetics was measured by determining urea isotopomer in urine after single injection of [¹⁵N₂]urea into the jugular vein. Both dry matter intake and milk yield were decreased under high ambient temperature. Intakes of total N and digestible N were decreased under high ambient temperature but urinary urea‐N excretion was increased. The ratio of urea‐N production to digestible N was increased, whereas the proportion of gut urea‐N entry to urea‐N production tended to be decreased under high ambient temperature. Neither return to the ornithine cycle, anabolic use nor fecal excretion of urea‐N recycled to the gut was affected by ambient temperature. Under high ambient temperature, renal clearance of plasma urea was not affected but the gut clearance was decreased. Increase of urea‐N production and reduction of gut urea‐N entry, in relative terms, were associated with increased urinary urea‐N excretion of lactating dairy cows in higher thermal environments.     

Immunohistochemical study of matrix metalloproteinases‐2 and ‐9, macrophage inflammatory protein‐2 and tissue inhibitors of matrix metalloproteinases‐1 and ‐2 in normal,purulonecrotic and fungal infected equine corneas

Objective Determine the effects of matrix metalloproteinases (MMPs)‐2, ‐9, macrophage inflammatory protein‐2 (MIP‐2), tissue inhibitors of matrix metalloproteinase (TIMP)‐1 and ‐2 by immunohistochemical expression in fungal affected and purulonecrotic corneas. Procedure Paraffin‐embedded equine corneal samples; normal (n = 9), fungal affected (FA; n = 26), and purulonecrotic without fungi (PN; n = 41) were evaluated immunohistochemically for MMP‐2, ‐9, MIP‐2, TIMP‐1 and ‐2. The number of immunoreactive inflammatory cells was counted and statistics analyzed. Western blot was performed to detect MMP‐2, MMP‐9, TIMP‐1 and TIMP‐2 proteins. Results Matrix metalloproteinases‐2, ‐9, MIP‐2, TIMP‐1 and ‐2 immunoreactivity was identified in corneal epithelium of normal corneas, and in corneal epithelium, inflammatory cells, keratocytes, and vascular endothelial cells of both FA and PN samples. Inflammatory cell immunoreactivity was significantly higher in FA and PN samples than in the normal corneas. There was positive correlation between MMP‐2 and MIP‐2, MMP‐9 and MIP‐2, and MMP‐9 and TIMP‐1 in inflammatory cell immunoreactivity in FA samples. There was positive correlation between MMP‐9 and MIP‐2, MMP‐9 and TIMP‐2, MIP‐2 and TIMP‐1, and MIP‐2 and TIMP‐2 in inflammatory cell immunoreactivity in PN samples. Western blot confirmed the presence of all four proteins in equine corneal samples. Conclusion Increased immunoreactivity of MMP‐2 and ‐9 in FA and PN samples is indirectly related to MIP‐2 through its role in neutrophil chemo‐attraction. Tissue inhibitors of matrix metalloproteinase‐1 and TIMP‐2 are up‐regulated in equine purulonecrotic and fungal keratitis secondary to MMP‐2 and MMP‐9 expression. The correlation between MMPs ‐2 and ‐9, MIP‐2, TIMPs ‐1 and ‐2 suggests that these proteins play a specific role in the pathogenesis of equine fungal keratitis.